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Copper‐Catalyzed Oxyboration of Unactivated Alkenes
Author(s) -
Itoh Taisuke,
Matsueda Takumi,
Shimizu Yohei,
Kanai Motomu
Publication year - 2015
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.201503329
Subject(s) - transmetalation , chemistry , alkoxide , alkyl , boron , catalysis , copper , structural isomer , combinatorial chemistry , medicinal chemistry , stereochemistry , organic chemistry
The first regiodivergent oxyboration of unactivated terminal alkenes is reported, using copper alkoxide as a catalyst, bis(pinacolato)diboron [(Bpin) 2 ] as a boron source, and (2,2,6,6‐tetramethylpiperidin‐1‐yl)oxyl (TEMPO) as an oxygen source. The reaction is compatible with various functional groups. Two regioisomers are selectively produced by selecting the appropriate ligands on copper. The products may be used as a linchpin precursor for various other functionalizations, and net processes such as carbooxygenation, aminooxygenation, and dioxygenation of alkenes can be achieved after CB bond transformations. Mechanistic studies indicate that the reaction involves the following steps: 1) Transmetalation between CuO t Bu and (Bpin) 2 to generate a borylcopper species; 2) regiodivergent borylcupration of alkenes; 3) oxidation of the thus‐generated CCu bond to give an alkyl radical; 4) trapping of the resulting alkyl radical by TEMPO.